Electrical fluid heater



June 8, 1954 H. F, BREMER ET A1. 2,680,802

ELECTRICAL FLUID HEATER Filed April l2, 1952 2 Sheets-Sheet l FROM wATEnSuPPLY INVENTOR.)` 62 #5eme/VN Ff azi/Ef 8( Jose/PH a. @oA/amro June 8,1954 H. F. BREMER ETAL 2,680,802

ELECTRICAL FLUID HEATER Filed April 12, 1952 2 Sheets-Sheet 2 ao a1 72imx INVENToRs 72a ao@ vel; 501; caoc 60d a HERMANN E BREMEN( YdosEPl-lA. GoNDoLr-'c Ta .5. y B

W Kiw- ATTORNEYS Patented June 8, 1954 UNITED STATES PATENT OFFICEELECTRICAL FLUID HEATER Application April 12, 1952, Serial No. 281,944

16 Claims. l

This invention relates to an electric heater adapted for the quickheating of a iiowing liquid stream, and is here disclosed in itsapplication to the heating of water for use in a hot coffee vendingmachine.

The heater of the present invention may be used in connection with anydevice which requires a supply of hot water in its operation, moreparticularly wherein the hot water supply must be delivered at or abouta predetermined temperature. Examples of such devices are hot coiTeevending machines, vending machines for other kinds of hot drinks, dishwashers, laundry machines, and the like.

Among the objects of the invention are to provider an electric hot-waterheater containing a multiplicity of heating units or sections throughwhich the water passes in succession, having different effectivecapacities for heat generation, whereby the device is suited forinstallation in different parts of the `country where the mineralcontent of the water supply, and thus its electrical conductivity, maybe widely different.

Another object of the invention is to provide a fluid heating devicewherein the length and cross-sectional area of the electrical paththrough the fluid can be accurately controlled under conditions ofquantity manufacture and rapid assembly.

This application is a continuation-in-part of copending application Ser.No. 134,754, filed December 23, 1949, for Electric Hot Water HeatingElement, now abandoned.

Reference is made to the accompanying drawings, in which Fig. l is afragmentary perspective View of a hot coiiee vending machine withportions broken away to show the interior construction thereof. In sucha machine, a hot water heater according to this invention may bepositioned within the sub-assembly I and delivers hot water through hose64 to the mixing chamber I 3.

Fig. 2 is a fragmentary horizontal sectional View on the line 2 2 ofFig. l showing the electrical heater if! of the present invention inplan.

Fig. 3 is a vertical sectional View of one form of electrical heatermade according to the present invention, taken on line 3-3 of Fig. 2.

Fig. 4 is a vertical longitudinal sectional View of a heater unitcontaining one electrode pair made according to a modified form of ourinvention.

Fig. 5 is a vertical longitudinal section through a heater embodying ourinvention comprising four units similar to the unit shown in Fig. 4.Fig. 5 also shows, diagrammatically, an example of an electrical circuitarrangement whereby the heater of the present invention may be connectedwith a source of electric power.

Fig. 6 is a fragmentary vertical longitudinal section, with parts inelevation and other parts omitted, of a heater embodying anothermodication of the present invention.

Referring to Figs. 1, 2 and 3, 10 represents the casing of a coffeedispensing machine in which there is disposed a reirigerating unit IIadapted to contain coffee and cream, a liquid sugar container I2, amixing chamber I3 connected with a water supply extending from anelectrical heater it of the present invention and located in subassemblyi5. I-Iot coffee is dispensed from a spout i5 into a cup I'I positionedin an opening in a door i8 that covers the iront of the apparatus.Connected to the mixing chamber I3 are magnetically operated valves I9,20 and 2| for controlling the flow of the various ingredients which makeup the coffee drink. The magnetic valves i9 and 263 lie within therefrigerating unit as through them must pass cream and liquid coiee thatmust be kept under refrigeration.

On the sub-assembly I5 is a set of switches 22 in a common casing 23 ofconventional construction which is connected to a source of currentsupply and these switches are electrically connected respectively bywires 24, 2E, 26 and 21 to terminal posts 28, 29, 3G and 3l respectivelyof the electrical heater I4.

The respective terminals are connected respectively with diiierentconductive sleeves 32, 33, Sli and 35, each constituting a secondaryelectrode, and located end-to-end. These sleeves, in the form of deviceshown in Fig. 3, are of the same internal diameter but of differentlengths and therefore of diierent internal surface areas. Positionedwithin these sleeves is a central drumshaped member 3G, constituting aprimary electrode, which is coaxially mounted with the sleeves and hasan external diameter smaller than the internal diameter of the sleeves,thus providing an annular space for water to flow between it and thesleeves. This central member or electrode 36 has annular grooves 3llocated adjacent sealed ends of the sleeves, as indicated at 38. Thesleeves are sealed and insulated from one another by such seals.

The central electrode 36 has threaded inlet and outlet end portions orprojections fil and 42 adapted to carry insulators 43 and 44respectively. The insulators i3 and 44 are respectively sealed to therespective end contact sleeves 32 and 35 by sealing washers 45 and 46respectively. The contact sleeves are kept properly spaced relative tothe peripheral surface of the electrode 36 by these insulating washers43 and 44. The washer i3 is held in place on the projection 4! by ametal washer i? which carries a sealing ring i3 and a securing nut t9.The securing nut t@ has a terminal to which is attached a Wire 52serving to place the electrode 3S in the electrical circuit. The waterenters the inlet portion el through opening 53 thereof and surrounds theelectrode to establish the electric circuit between the drumliheelectrode 36 and the sleeve electrodes 32, 33, 3d and 35. With thiscircuit established, the Water will become quickly heated because of itsresistance to current ow.

The insulating washer All is held on portion by a washer 55 having aseal 5t and a nut 5l threaded on the portion 52. The outlet portion 42has an opening 58 through which the hot water will be discharged.

Surrounding the sleeve electrodes are a plurality of insulating sleeves@l carrying respectively the terminal posts 28, 2Q, 3e and 3l. rihesleeves tightly receive the sleeve electrodes and the seals 35. Theterminal posts 23, 29, e@ and 3l may be tapped into the sleeveelectrodes and are locked respectively by lock` nuts Sii of therespective screws. A. second nut 53 may be provided upon each terminalpost to effect the connection of the respective Wires EIS, 25, 2&5 and2l thereto.

The outlet portion i2 of the central electrode may be connected by ahose iid with the mixing member I3. Water is led to the inlet portion ilof the electrode 3G by a pipe 65 leading from a water supply. On thesub-assembly is a gauge 65 from which the pressure of the water can bedetermined. A regulating valve element 5l can control the rate of waterflow. The heater can be supported by straps G3 and 69 nxed to thesubassembly l5.

When making an adjustment for the proper current to be supplied to theheater, to heat the Water to the desired degree of temperature, anammeter 'il is provided. The meter reading is taken as the differentswitches 22 are thrown on and off. When the meter shows that the propercurrent is flowing, the heater will have 1eeen properly adjusted for thegiven water condition. Any combination of the switches t2 can be used,if, by the use of one sleeve electrode alone, the desired amperage llowis not provided.

eferring to the modifications shown in Figs. 4, 5 and 6, the heater mayalso be made in the forin of a series of heater units, one of which isshown in ig. e, and four of which interconnected together shown in Fig.5 and (in another modification) in Fig. 6.

Referring particularly to TEig. 4l, the primary electrode is machinedfrom solid metal in such form that it consists of a drum l2 ofessentially cylindrical shape, said drum having on each end thereof ahub-like extension l', le, each hub being coaxial with and constitutinga prolongation of the central axis of drum l2, and being ofsubstantially smaller diameter than the diameter of drum l2. The hubslt, 'lil are formed integrally with drum l2. Within each hub is alongitudinal drilling l5, l@ constituting a water passageway locatedaxially and extending longitudinally thereof and penetrating a shortdistance into the drum l2. Lateral drillings ll, lil, of which there maybe several at each end of the drum l2, communicate with longitudinaldrillings l5, 'it and form with said last-mentioned drillings a waterpassageway whereby water entering at the extremity of one hub may passtherethrough, thence to the surface of drum l2 and finally to theextremity of the other hub. Preferably,

though not necessarily, drum l2 be beveled as at 19. Such bevel servesas a trap for sediment and the like.

.e metallic sleeve @il constitutes a secondary electrode and, having aninside diameter slightly larger than the outside diameter of drum l2, ismounted coaxially with drum 'lll and in nested relation therewith, bythe supporting inea-ns hereinafter described, to iorm an annular spaceor channel @l between drum 'l2 and sleeve 853. Thus, water passing incontact with the surface of drum i2 is conned between drum i2 and sleevedil, which are respectively the primary and secondary electrodes of theheater unit.

The above-mentioned electrodes be secured in the described position byany suitable means. One such means comprises a pair of discs S2, t3formed of insulating material, such for example as ceramic material,having a central opening te, adapted to nt upon hubs 'i3 and '54,respectively. Discs S2, et in turn engage the opposite ends of sleevetill, and are pressed thereagainst to maintain sleeve 3S in its properposition with relation to drum l2.

Sealing rings are preferably inserted between the ends of sleeve anddiscs Sie and 83, to prevent leakage of water.

Hubs 'i3 and lil are externally screw-threaded for engagement therewithof couplers 953, Sila or other attachment fixtures. Sealing rings Sg, 8Bare adapted to be compressed against discs 82, 33 by means of couplersSil, Std which are internally screw-threaded at ill, ille and areadapted to mesh 'with screw threads on the external surface of the hubs.The water-transmitting function of couplers Sil, will appear inconnection with the description of Fig. 5. Another function of thecouplers, in combination with the threads on the hubs, is to maintainsleeve 39 under longitudinal compression and thus secure the electrodeassembly in predetermined iixed position.

Where the mineral content of the water and the rate of flow is known inadvance, a single unit as shown in Fie. 4i can be the size and surfacearea of the electrodes being predetermined to effect the desired rise inwater temperature at the available voltage. l heater so made of a singleelectrode pair is an efficient instrument for heating iiuid passingthrough it. lts lack of ilexibility, however, especially Where theavailable voltage is constant, is the reason why more than one such pairmay be arranged in series in the path of fluid flow and in parallel inthe path of current flow, as set forth below.

Where the mineral content of the supply water varies widely fromlocation to location, a single electrode pair, as above described, willproduce different heating eilects for the same rate of water flow. Themore ions there are in solution, the lower will be the electricalresistance of a water pathway, of given. cross-sectional area and offixed length. When the rate oi water rlow and the applied voltageremains the saine, the heating eifect is proportional to the amper-eswhich pass through the water. Since an appliance utilizing hot water-orexample, a hot coiee vending machinerequires at each cycle of operationa predetermined amount of hot Water, at a predetermined deliverytemperature, and at about a predetermined rate of flow, and must producethis result by the use of the llo volt current which is standard in mostinstallations, it will be apparent that the iiipcrtaot variable from onelocation to another is the dr." rence in ion content, and hence ofelectrical resistance, of local Water supplies. These diierences are infact so great that the range of adjustment required in an electricalheater suited to meet all water condtions commonly encountered shouldpreferably admit of reducing current ow to at least onetenth of themaximum which the device will handle.

In order to achieve such a wide range of adjustment in a standarddevice, a series of heater units, such as that shown in Fig. 4,`may beconnected together in end-to-end relation by means of a series ofcouplers. In Fig. 5 there is shown a heater made up of four such units,but any number may be used and this particular number is shown forillustration only. In this case there are three couplers interposedbetween adjoining heater units, and at one end (the left end as seen inFig. 5) there is provided an inlet coupler S2 adapted to bescrew-threadedly engaged with the hub at the left-hand end of the rstheater unit, and to afford attachment for a pipe 03 through which wateris fed to the device from a suitable source of supply. At the oppositeend oi the heater (the right-hand end as seen in Fig. 5) there isattached a delivery coupler 94 which is screw-threadedly engaged withthe hub at the right-hand end of the last heater unit in the series, andis provided with an end portion or nozzle 95 to which a rubber hose orthe like may be attached. In this device water flows through the severalheating units in series.

The several heating units as shown in Fig. 5 may be enclosed within atube 95 of insulating material, and electrical terminals ill, 00, 99, 00

may be tapped through tube il@ to a point of electrical contact andmechanical securement with each of the sleeves 80d, 300, 00e and 80d ofthe respective heater units shown. An electri- Cal terminal itil may besecured upon inlet coupler 92. The electrical current source,diagrammatically indicated at 110 v. in Fig. 5, is preferably connectedin such manner that one side of the current is secured to terminal il,and the other side of the current is connected to each of the terminalsel, 98, 99 and E00 through a separate switch, as shown diagrammatically,such that the several sleeves 00a, 80h, 30e and iild are connected inparallel in the circuit, and each is under the control of a separatemanually operable switch. Thus, when four heater units are arranged asshown in Fig. 5, any one or more of them may be energized, according tothe requirements of the particular water which the machine is to handle,If desired, an insulating connection may be interposed between terminall0! and pipe 93.

When necessary to obtain a wide range of heating capabilities, theseveral electrode pairs shown in Fig. 5 may be made in such manner that,with the same type of water, the resistance to passage of electricalcurrent of different electrode pairs may be different. In the deviceshown in Fig. 3 this was accomplished, as pointed out above, by varyingthe length of the sleeves. In the form of device Shown in Fig. 5 thismay be accomplished by making the drums of different external diameteror surface areas; and in the form shown in Fig. 6 by making the sleevesof different internal diameter or internal surface areas.

In Fig. 5 the drums 12d, 12b, 12e and ld are of progressively decreasingexternal diameter. This is shown in Fig. 5 to an exaggerated degree forthe sake of clarity, the internal diameter of the sleeves remaining thesame in all four units. In Fig. 6 there is illustrated a four-unitheater wherein the drums 12a, 12b, 12o and 12d are of the same diameterand sleeves 80a, 80h, 80e and 80d are of progressively increasinginterior diameter in successive units counting from left to right inFig. 6.

In either case the result is that the electrical path from sleeve 80 todrum l2, through annular space Si, is of different length in dilrerentheater units, and furthermore the area of one of the electrodes (eitherthe sleeve or the drum) is different in the different heater units.

As a specic example of a hot-water heater which has successfully handleda wide variety of water conditions encountered in communities in thenortheastern section of the United States, for use in a hot coffeevending machine, the following particulars are given: At a waterpressure oi about 6 lbs. per sq. in., and a starting temperature ofabout 70 F., the heater is designed to handle a flow of about one ounceof water per second and to raise the water to a temperature of 180 F.during a time of passage of about one second. The electrical supply isassumed to be at about 110 or 115 volts. At this voltage, and in orderto raise one ounce of water per second from a temperature of about '70F. to about 180' F., it has been found that about ten amperes of currentmust pass through the water, whatever may be its condition orconductivity.

If the water is hard-i. e., has a high content of ions in solution, thewater will be more conductive, and consequently too much current willflow and the water will be heated to too high a temperature. Under suchconditions as these, it is necessary to reduce the number of units, orto increase the length of the electrical path through the water, or tomake the electrode area smaller, or some combination of all of thesethings. These compensations may be accomplished in the form of deviceshown in Fig. 5 by making the four sleeves of a uniform length of about11/2 inches and a uniform internal diameter of l inch. The fourdrumshave external diameters respectively of .937 inch, .915 inch, .900inch and .885 inch and are of the same length slightly less than thelength of the sleeves. Under the particular conditions stated the lengthof the electrical pathway in the flowing water, in the four heater unitsrespectively, is 0.0315, 0.0425, 0.05 and 0.0575 inch, measuringradially the gap between the surface of the drum and the surface ofthesleeve.

By making the different heater units of different gap, or differentelectrode area, a wider and more accurate range of choice in adjustmentcan be obtained than would be the case if the heater units were thesame. If it be supposed that one heater has a heating capacity of oneunit, another of two, another of three, and another of four, it ispossible by combinations of these to adjust the group of heaters for anyheat capacity between one and ten units thereof.

The invention is not limited to any particular shape or form hereinshown, except Where stated to be of the essence, and includes allmodifications thereof which are comprehended within the attached claims.

What is claimed is:

l. An electric fluid heater comprising a solid drum-shaped primaryelectrode having at each of its ends and formed integrally therewith anaxially disposed hub-like extension of smaller diameter than the drum, alongitudinal fluid passageway extending axially of each of said hublikeextensions from the outer end thereof towards the drum-'shaped centralportion of the electrode and terminating therein, lateral .fluidpassageways communicating with the passageways rst named, a sleeveconstituting a second-- ary electrode whose inner diameter is greaterthan the outer diameter of the drum-shaped portion of the primaryelectrode, and two members of insulating material each having an openingengaged upon the hub-like extension at opposite ends of the primaryelectrode, the ends of said sleeve being engaged between the said twoinsulating members and supported thereby in coaxial relation with andsurrounding the drumshaped portion of the primary electrode, whereby uidentering at one of the hub-like extensions is caused to flow between theouter surface of the drum-shaped primary electrode and the inner surfaceof the sleeve in a direction generally parallel to the axes of saidelectrodes and thence out the other of said hub-like extensions, andmeans to conduct electric current to said electrodes while fluid owsbetween them.

2. An electric iiuid heater comprising a series of solid metallic drumsconstituting primary electrodes and electrically connected together, ahublike extension at each end of each drum and of 'smaller diameter thanthe drum, metallic Sleeves constituting secondary electrodes equal innurnber to the number of drums, each of said drums and one of saidsleeves together Aforming an elec` trede pair mounted coaxially and innested relation with the inner diameter of the sleeve being larger thanthe outer diameter of the drum thus forming an annular space betweenthem, insulating supporting members engaging the opposite ends of saidelectrodes to secure them in position and insulate each sleeve from eachother sleeve, interconnecting fluid passageways extending axially ofsaid hub-like extensions and laterally within each drum whereby fluidentering at one of said hubdike extensions is caused to iiow in theannular space between the drum and sleeve of each electrode pair andthence to another of said hub-like extensions, thus passing through eachof said electrode pairs in series, and means for selec'- tivelysupplying electric current to any of said 'electrode pairs in parallelto control the amount of heat imparted to the fluid.

3. An electric fluid heater as described in claim 2 wherein at least twoof said sleeves are of different internal surface area.

4. An electric iiuid heater as described in claim 2 wherein at least twoof said sleeves are of different length.

5. An electric iiuid heater as described in claim 2 wherein at least twoof said sleeves are of different internal diameter.

6. An electric fluid heater as described in claim 2 wherein at least twoof said drums are of different `external surface area.

7. An electric iiuid heater as described in claim 2 wherein at least twoof said drums are of different external diameter.

8. An electric fluid heater comprising a solid primary electrode whoseouter surface in a plane at right angles to its axis is circular inshape, a metallic tubular extension of less diameter than said electrodeprojecting at each end thereof and coaxial therewith, said tubularextensions being adapted to serve as the supports for said electrode andalso to conduct fluid to and from the heater, a secondary electrodesurrounding and coaxial with the primary electrode and having an innersurface which in the plane aforesaid is circular in shape and greater indiameter than the diameter of the circular outer surface of the primaryelectrode, two members of insulating material each having an openingtherein adapted to engage one of said tubular extensions and eachengaging an opposite end of the secondary electrode and thus supportingsaid electrodes in nested and coaxial relation in such manner that thetwo electrodes define an annular fluid space between the outer surfaceof the primary electrode and the inner surface of the secondaryelectrode, uid passageways at right-angles to the axis of saidelectrodes interconnecting the interiors of said tubular extensionsrespectively with opposite ends of said annular space whereby fluidentering at one of said tubular extensions is caused to flow in saidannular space in a direction generally lengthwise of the common axis ofsaid electrodes and thence out the other of said tubular extensions, andmeans to conduct electric current to said electrodes while fluid flowsbetween them.

9. An electric fluid heater as described in claim 8 wherein one oi saidelectrodes is divided into segments insulated from each other andadapted to be separately energized in parallel across the currentsource.

10. An electric iiuid heater as described in claim 8 wherein thesecondary electrode is divided into segments insulated from each otherand adapted to be separately energized in parallel across the currentsource.

11. An electric fluid heater as described in claim 8 wherein one of saidelectrodes is divided into segments insulated from each other and atleast two of said segments are of diierent surface area.

12. An electric nuid heater as described in claim 8 wherein one of saidelectrodes is divided into segments insulated from each other and atleast two of said segments are of different length.

13. An electric iiuid heater as described in claim 8 wherein thesecondary electrode is divided into segments insulated from each otherand at least two of said segments have inner surfaces of differentdiameter.

14. An electric iluid heater as described in claim 8 wherein thesecondary electrode is divided into segments insulated from each other,the primary electrode is divided into segments electrically connected toeach other, and each segment of the secondary electrode forms with acorresponding segment of the primary electrode a space for iiow of iiuidbetween them.

15. An electric iuid heater as described in claim 8 wherein thesecondary electrode is di* vided into segments insulated from eachother, the primary electrode is divided into segments electricallyconnected to each other, and at least two of the primary electrodesegments have outer surfaces of different diameter.

16. An electric iiuid heater as described in claim 8 wherein thesecondary electrode is divided into segments insulated from each other,the primary electrode is divided into segments electrically connected toeach other, and at least two of the primary electrode segments are ofdif ferent external surface area.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 1,668,293 Van Tuyl May 1, 1928 1,730,016 Rudd Oct. 1, 19292,100,329 Getchell Nov. 30, 1937

